My rims size:
Rear 18 X 9.5
Front 18 X 8.5

Im looking to spend about 200-350..also would I need offsets?

 

Rim size has nothing to do with springs. Overall tire diameter does depending on what drop you want, or if you want a drop at all.

Offsets of your wheels determine if they get lost in the car, sit flush or hang out.

You are talking about many different things.

 

all rims have an off set....what are you looking for? a mild, or slammed look? search around for tanabe, swift and tein springs and find a setup that you like